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The disappearance of birds in the fall season may at first seem unsettling, but you have no need to worry. Many of the birds in North America are, in fact, migratory. This seasonal migration presumably evolved as a reproductive strategy to help birds take advantage of areas that are
more productive and provided less competition. During the summer months, many migratory birds breed in North America where an abundant insect supply and a more hospitable climate exist, as compared to Central and South America.
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Migration distances vary greatly among species and among individual birds of the same species. For example short-distances migrates, like the Black-capped vireo, an endangered bird that breeds in Texas, travel 400-1,250 miles between its wintering and breeding grounds. Long-distance migrates, like the Blackpoll warbler, a wood warbler that breeds in Alaska, travel 2,500-5,000 miles between its winter and breeding grounds. Many small long-distance migratory birds have evolved to migrate at night to avoid predatory raptors. Before migration many birds will pack on large scores of fat to help supply them with energy for their long journey. During some water crossings, such as the Gulf of Mexico,
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approximately a 500-mile nonstop trip, birds will use most of their stored energy resulting in the loss of half their body weight.
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Many people may wonder how a bird weighing less than a half ounce, as most warblers are, find their way thousands of miles to and from the wintering and breeding grounds. Research has shown that birds use a combination of the following sources to help orientate their travel during migration: 1) topographical features, 2) stars, 3) sun, 4) Earth's magnetic field and 5) odors.
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Migration for birds is an arduous task and many individuals do not complete the trip successfully. Predators, exhaustion, weather and departure date all can have a negative effect on the survival of birds during migration. Perhaps most surprising to people, the leading cause of avian mortality during migration is probably window strikes. Recently, this has become a serious conservation concern. Annual mortalities have been estimated at over 100-million birds dying from brain hemorrhaging caused by window
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strikes. For suggestions on how to deter birds from striking your windows visit www.sialis.org/windowstrikes.htm
More questions check out: www.closertonature.com/outdoors/bird-migration.htm
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As
Texans, we like to lay claim to anything and everything we can, y’all.
Well friends, the Texas Spiny Lizard is no exception. Although these
critters can be found from the southern border of Oklahoma to Central
America, we’ll take the credit, thank you very much. In Texas, they
inhabit a good majority of the state and have adapted to life in many
of the wide variety of ecological regions (click here for details)
we have to offer. It’s only fair we dub these devils Texans, as
“everything’s bigger in Texas” and they are one of the largest
tree-inhabiting lizards in North America. Now mind you large for a
lizard ain’t like our longhorns, but an adult spiny averages between 7
½ to 11 inches from head to tail. To tail the truth, that’s a doggone
big lizard. |
| Primarily, the
Texas Spiny Lizard will have a rusty brown to dark gray coloration,
with a wild pattern of dark and light wavy lines. Their large size and
large “spiny” scales make them hard to swallow, and their long toes,
large claws, and long tails enable these fellars to flutter up a tree
in a flash. These key adaptations help them escape predators; such as
birds, snakes, and other various vicious varmints. More than not, you
will hear’em before you see’em, and I’ll tell ya folks, you’d be better
off throwin’ your lasso round a rain-cloud than tryin’ to tackle these
true Texas treasures. |  |
| In
Austin, Texas Spiny Lizards are everywhere; from city-limit fence posts
to the First Street Bridge. Heck, they keep Austin weird by adding to
the tremendous diversity that fills the City and turns heads. You can
bet your boots my head turns every time I see a spiny; so keep your
ears on and your eyes open, good buddy, because these buckaroos are
mighty fine neighbors and authentic Austinites. |
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The Great Blue Heron would certainly be on the shortlist of most
recognizable migratory birds in the state of Texas. In fact, this
well-traveled Avian can be witnessed anywhere in the contiguous United
States depending on the time of year. Their range extends north into
the southern half of Canada, south throughout Central America, and
along the northern coast of South America. |
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Prestigious in appearance, this bird captivates observers with a
graceful strut, while providing comic relief with a squawk that echoes
from their beak (Click here to listen).
Onlookers find them equally hypnotizing in flight, with their
streamlined frame and tremendous wingspan, which averages around
six-feet in width for adults. Utilizing the tools they have been given,
the Great Blue Heron has long legs, a long neck, and a long beak which
are fantastic adaptations for fishing in shallow waters, but these
gluttons will feed on almost anything they are able to apprehend,
including amphibians, reptiles, small mammals, and even other birds.
Although they are capable of feasting on such a diverse diet, one of
the most common modes of death for this species comes from choking on
fish far too large to swallow.
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Here in Austin, bird watchers should expect to find the Great Blue
Heron nesting in trees or foraging along shallow shorelines surrounding
the large bodies of water that add to the uniqueness of Austin. |
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As seen in the photograph above (taken at Town Lake, Austin, Texas;
courtesy of the Lower Colorado River Authority), the Great Blue Heron
does not come across as bashful by any means, and so long as they are
not approached in a threatening manor, they will usually hang out with
everyone else enjoying the many pleasures aquatic recreation has to
offer. So the next time your out on the water, keep an eye open for
this magnificent creature to find out for yourself what makes the Great
Blue Heron great indeed! |
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